Breslow et al., e.g., J. Amer. Chem. Soc. 96 (1974) 1973, ibid. 96 (1974) 6791, describe the chlorination of steroids which have been esterified at the 3.alpha.-position wherein the tertiary carbon atom in the 9-position is chlorinated with iodobenzene dichloride under the influence of light, and subsequently, hydrogen chloride is cleaved off with the formation of a 9,11-double bond.
The disadvantage in the foregoing process is that it has utility in only those steroids which have no carboxy group or no unprotected carbonyl group in the 17.beta.-side chain. In accordance with the present invention, it has been found that 9.alpha.-chloro-3-oxo-androst-4-ene-17.beta.-carboxylic acids can be selectively obtained in the unprotected form. It has further been found that the chlorination is effected selectively in the 9-position which is unexpected since, from the work of Halpern, e.g., Chem. & Ind. (1962), 1571, it was known that steroids with double bonds react with iodobenzene dichloride to give the corresponding .alpha.-dichlorosteroids.